The Robert Benjamin Ablin Foundation for Cancer Research, Tucson, AZ 85705, USA.
Biomark Med. 2011 Aug;5(4):515-26. doi: 10.2217/bmm.11.53.
Prostate-specific antigen (PSA) is a protein produced by the prostate, and this protein may be elevated for several reasons, including prostatitis, benign prostatic hypertrophy and/or cancer. PSA is not cancer-specific, cannot be used as a cancer marker and it has been demonstrated that there is no level of PSA that is definitive for prostate cancer. The value of the PSA test varies when used for screening, diagnosis, prognosis or as a signal of disease recurrence. Misuse of the test for screening has created unnecessary anxiety and costs, and has led to the significant overdiagnosis and overtreatment of men. More important than whether or not to screen is how one acts upon the data from a single test; with the exception of extremely high double- or triple-digit levels of PSA, it is prudent only to use a single PSA determination as a baseline, with biopsy and cancer treatment reserved for those with significant PSA changes over time, or for those with clinical manifestations mandating immediate therapy. Using the PSA test to monitor disease progression or recurrence is appropriate, provided one understands that absolute levels of PSA are rarely meaningful; it is the relative change in PSA levels over time that provides insight, but not definitive proof of a cancerous condition necessitating therapy. PSA secretion is under hormonal control and thus PSA levels may be affected differently by the type of drug therapy, by the stage of a patients' disease, and by genetic factors suggesting some men are 'high PSA producers'. Until a validated alternative test for prostate cancer is found and adopted, the current flawed PSA test needs to be used more judiciously and not used for routine screening as studies have demonstrated that screening, as defined, does not lead to a reduction in patient mortality. All men, their families and their physicians need to understand the significant limitations of PSA testing.
前列腺特异性抗原（PSA）是前列腺产生的一种蛋白质，这种蛋白质可能会升高，原因包括前列腺炎、良性前列腺增生和/或癌症。PSA 不是癌症特异性的，不能作为癌症标志物，并且已经证明没有 PSA 水平可以确定为前列腺癌。PSA 测试的价值在用于筛查、诊断、预后或作为疾病复发的信号时会有所不同。PSA 测试的滥用导致了不必要的焦虑和成本，并且导致了男性的过度诊断和过度治疗。比是否进行筛查更重要的是如何根据单次测试的数据采取行动；除了 PSA 水平极高的双或三倍以上的水平外，仅使用单个 PSA 测定作为基线是谨慎的，对于那些 PSA 随时间显著变化的患者，或者对于那些有临床表现需要立即治疗的患者，进行活检和癌症治疗。使用 PSA 测试监测疾病进展或复发是合适的，前提是要理解 PSA 水平的绝对值很少有意义；只有 PSA 水平随时间的相对变化才能提供洞察力，但不能确定需要治疗的癌症状况的确定性证据。PSA 分泌受激素控制，因此 PSA 水平可能会因药物治疗类型、患者疾病阶段和遗传因素而受到不同影响，这些因素表明一些男性是“高 PSA 产生者”。在找到并采用经验证的前列腺癌替代测试之前，当前有缺陷的 PSA 测试需要更谨慎地使用，而不能用于常规筛查，因为研究表明，定义的筛查不会降低患者死亡率。所有男性、他们的家人和他们的医生都需要了解 PSA 检测的显著局限性。
